1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    *
5    *
6    *
7    * The contents of this file are subject to the terms of the Liferay Enterprise
8    * Subscription License ("License"). You may not use this file except in
9    * compliance with the License. You can obtain a copy of the License by
10   * contacting Liferay, Inc. See the License for the specific language governing
11   * permissions and limitations under the License, including but not limited to
12   * distribution rights of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.portal.kernel.util;
24  
25  import java.util.AbstractSet;
26  import java.util.Iterator;
27  import java.util.Map;
28  import java.util.Set;
29  import java.util.concurrent.ConcurrentHashMap;
30  
31  /**
32   * <a href="ConcurrentHashSet.java.html"><b><i>View Source</i></b></a>
33   *
34   * @author Brian Wing Shun Chan
35   */
36  public class ConcurrentHashSet<E> extends AbstractSet<E> {
37  
38      public ConcurrentHashSet() {
39          _map = new ConcurrentHashMap<E, String>();
40      }
41  
42      public ConcurrentHashSet(int capacity) {
43          _map = new ConcurrentHashMap<E, String>(capacity);
44      }
45  
46      public ConcurrentHashSet(Set<E> set) {
47          Iterator<E> itr = set.iterator();
48  
49          while (itr.hasNext()) {
50              E e = itr.next();
51  
52              _map.put(e, StringPool.BLANK);
53          }
54      }
55  
56      public boolean add(E e) {
57          if (_map.put(e, StringPool.BLANK) == null) {
58              return true;
59          }
60          else {
61              return false;
62          }
63      }
64  
65      public void clear() {
66          _map.clear();
67      }
68  
69      public boolean contains(Object obj) {
70          if (_map.containsKey(obj)) {
71              return true;
72          }
73          else {
74              return false;
75          }
76      }
77  
78      public Iterator<E> iterator() {
79          return _map.keySet().iterator();
80      }
81  
82      public boolean remove(Object obj) {
83          if (_map.remove(obj) == null) {
84              return false;
85          }
86          else {
87              return true;
88          }
89      }
90  
91      public int size() {
92          return _map.size();
93      }
94  
95      private Map<E, String> _map;
96  
97  }